When you're on firmware 9.2 or below you can get Gateway OR set up CFW to play cia's, if you're on 10.3 you can downgrade to 9.2 and continue with the options there. If you're above 10.3, your only bet is to go with Sky3DS+.

It also depends on what you want to do with it. Just play games with it? Or also hack stuff and play SNES/GBA/DS games?